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cklee
Participant

Join Date: Oct 2012
Posts: 1

AC or DC Rotor Drop Test Problem

10/18/2012 3:32 AM

Hi

I had a 3 phase 450V AC 800KW alternator kept in the warehouse for serveral years(4 years). Now we had put it into service.So we had sent the alternator for some workshop for testing.

Ac volt drop test was applied and the result was found to be faulty.

My question is why only AC volt drop test apply not DC or current .

What are the proper require test for the alternator rotor?.

Can anyone advise?.
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PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#1

Re: AC or DC Rotor drop test problem

10/18/2012 3:48 AM

Sure. The manufacturer of the alternator will be able to advise and it has got to be worth a couple of telephone calls if it isn't in the user manual supplied with it. Go for it; make a few calls.

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Joshi
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Join Date: Oct 2007
Location: India
Posts: 1246
Good Answers: 34
#2

Re: AC or DC Rotor drop test problem

10/18/2012 4:05 AM

Alternator means it is an AC generator

"why only AC volt drop test apply not DC or current"

Because it is an alternator. Please check these LINKS about rotor testing.
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leveles
Guru

Join Date: Jan 2008
Posts: 1753
Good Answers: 59
#3

Re: AC or DC Rotor Drop Test Problem

10/18/2012 11:13 PM

I hope you have some english spelling help. The generator does not need a drop test, but a droop test: losing voltage with increased load.

Other than that, get it into service. Period. Measure it, and if it only produces, say 95%, who cares?!? Live with it.
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rishan444
Participant

Join Date: Oct 2012
Posts: 1
#4

Re: AC or DC Rotor Drop Test Problem

10/19/2012 9:06 AM

first check the diode plate. then check the insulation of main rotor winding it must be more than 1megaohms. then check the exiting rotor insulation it also must be more than 1megaohms.
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pcchatur
Power-User

Join Date: Mar 2010
Location: BHOPAL, INDIA
Posts: 201
Good Answers: 20
#5

Re: AC or DC Rotor Drop Test Problem

11/04/2012 5:28 AM

Insulation resistance test on stator windings and rotor windings must be done. Also insulation test among the 3 phases of stator winding must be conducted. You may also like to perform impedance measurement for all windings and compare the value with earlier values. This would give the idea of presence for any inter-turn short in windings.
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Previous in Forum: Full Details for Designing Capacitor Bank for a System   Next in Forum: Communication PC-PCL Hitachi EC2

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